Device with a Decoupled Cylinder Sleeve

ABSTRACT

A device includes a cylinder sleeve ( 3, 13 ), which is at least indirectly arranged at a housing ( 7 ) and at least three radially outward extending journals ( 5 ). Each journal ( 5 ) comes to rest, at least on one side, against a roller element (6 a , 6 b ) accommodated at the housing ( 7 ) in order to support the cylinder sleeve ( 3, 13 ) on the housing ( 7 ) in at least one tangential direction. The device can be designed, in particular, as a planetary transmission or as an electric machine.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related and claims priority to 102020201749.2filed in the German Patent Office on Feb. 12, 2020 and is a U.S.national phase of PCT/EP2021/050888 filed in the European Patent Officeon Jan. 18, 2021, both of which are incorporated by reference in theirentirety for all purposes.

FIELD OF THE INVENTION

The invention relates generally to a device having a cylinder sleeve,which is at least indirectly supported on a housing. The inventionfurther relates generally to a device designed as a planetarytransmission as well as to a device designed as an electric machine.

BACKGROUND

DE 10 2011 076 521 A1 describes a housing-side fastening arrangement ofa ring gear of a planetary gear set having a bearing shield forsupporting an output shaft of the planetary gear set for an electricvehicle drive system. Between the bearing shield and a ring gear carrieraccommodating the ring gear, a connecting section is provided fortransmitting the ring gear torque, wherein the connecting section isconfigured such that the connecting section has at least a lower radialrigidity with respect to the ring gear carrier.

SUMMARY OF THE INVENTION

Example aspects of the present invention provide a device, whichimplements a structurally easily implementable acoustic vibrationdecoupling.

A device according to example aspects of the invention includes acylinder sleeve, which is at least indirectly arranged at a housing andincludes at least three radially outward extending journals. Eachjournal comes to rest, at least on one side, against a roller elementaccommodated at the housing in order to support the cylinder sleeve onthe housing in at least one tangential direction. In other words, thecylinder sleeve is axially accommodated at least partially in astationarily situated housing and is supported, via the journalsarranged at the particular roller element, on the housing and, in fact,essentially tangentially. Consequently, a torque acting on the cylindersleeve is introduced or redirected tangentially into the housing via thejournals and the roller elements. The particular journal is displaceablein the radial direction in relation to the housing and, in the process,can roll on the particular roller element.

Preferably, each journal is arranged between two roller elementsaccommodated at the housing. This means, two roller elements in eachcase are arranged in one recess on an internal-shell wall surface of thehousing and, between themselves, accommodate one of the journals fixedlyconnected to the cylinder sleeve. The roller elements are preferablydesigned as cylindrical pivots, rollers, or pins and extend essentiallyin parallel to the longitudinal axis of the cylinder sleeve such thatthese make it possible for the journal to roll in the radial direction.Consequently, the roller elements are movably arranged in the radialdirection of the journal such that the cylinder sleeve can move radiallyin relation to the housing. The journals are arranged essentiallyperpendicularly to the longitudinal axis of the cylinder housing andextend radially outward relative to the longitudinal axis of thecylinder sleeve. There is no fixed connection between the journals andthe associated roller elements. Rather, the journals are supportedtangentially on the housing via the particular roller element as afunction of the torque applied at the cylinder housing. Therefore,contact between the journal and the particular roller element is notpresent at all times. Rather, in the case of a positive torque, theparticular journal can come to rest against one of the two rollerelements accommodated in the recess of the housing and, in the case of atorque acting counter thereto, can come to rest against the particularother roller element accommodated in the recess of the housing. In otherwords, a torque is introduced into the housing in the tangentialdirection regardless of the direction. A radial introduction of thetorque into the housing is prevented in this way.

The roller elements make it possible that the particular journals comingto rest thereon as a function of the acting torque can roll or glide onthe particular roller element when the cylinder sleeve moves radially.The journals are therefore arranged so as to be movable in the radialdirection between the particular two roller elements such that there isa radial freedom of motion of the cylinder sleeve in relation to thehousing. In other words, the journals do not rest radially against thehousing. Due to the radial freedom of motion, which the movable rollerelements of the cylinder sleeve offer, a radial excitation or a radialdeformation of the cylinder sleeve can be nearly completely absorbed bythe system. Due to the suitable arrangement of the journals on thecylinder housing, it is therefore achieved that the cylinder sleeve isalways supported against the housing in the tangential direction.Consequently, radially acting forces of the cylinder sleeve are alsodirected tangentially into the housing.

Preferably, the journals are arranged uniformly distributed on an outercircumferential surface of the cylinder sleeve in order to implement auniform distribution of force or transmission of force from the cylinderhousing into the housing. In the case of four journals, these aretherefore arranged at the quarter points on the outer circumference ofthe cylinder sleeve. In the case of three journals, these aredistributed at the third points. Moreover, it is conceivable that thejournals are arranged on an axial end face of the cylinder sleeve andextend radially outward.

Preferably, there is linear contact between the journals and theparticular roller elements. Therefore, the journals also extend over atleast a portion of the axial length of the cylinder sleeve. Preferably,the journals are as long as the axial length of the ring gear such thateach journal has a particular contact surface, in any circumferentialdirection, for contacting with a particular roller element in order tobe able to transmit a greater load in comparison to a point contact.

Further preferably, the journals are press-fit into recesses on thecylinder sleeve. The recesses are formed on the outer circumference ofthe cylinder sleeve and, further preferably, designed as axial grooves.This simplifies the manufacture of the cylinder sleeve, since thejournals are only subsequently fixedly connected with the cylindersleeve and press-fit into the particular groove. Alternatively, thejournals are integrally bonded with the cylinder sleeve. In other words,the journals can also be welded to the cylinder sleeve.

Example aspects of the invention incorporate the technical teaching thatthe journals and the roller elements are arranged in the axial directionat least indirectly between a shoulder of the housing and a securingring. As a result, there is an additional axial support of the cylindersleeve on the housing. The securing ring can be designed, for example,as a snap ring and, moreover, can be partially accommodated in acircumferential groove on the inner circumference of the housing inorder to direct the axial forces out of the cylinder sleeve into thehousing and axially support the cylinder sleeve on the housing. Theshoulder is preferably integrally connected with the housing or isintegrally formed thereon.

A thrust washer is arranged between the securing ring and the journalsin order to enlarge an axial contact surface. Therefore, the rollerelements and the cylinder sleeve are axially tensioned between theshoulder of the housing and the thrust washer, which is axially securedby the securing ring.

Preferably, at least one portion of the roller elements have unequalouter diameters. It is conceivable that the outer diameter of only oneroller element differs from the other roller elements, that the outerdiameters of multiple roller elements differ from the outer diameters ofthe other roller elements, or that the outer diameters of all rollerelements differ from one another. As a result, a compensation ofmanufacturing tolerances can be implemented and the positioning of thecylinder sleeve in the space can be adapted by suitably varying theroller diameter. In this way, in addition, a nearly play-free system isimplemented.

According to one exemplary embodiment, the device is designed as aplanetary transmission including a sun gear, a ring gear, and at leastone planetary gear set having multiple planet gears, which are at leastindirectly rotatably mounted on a planet carrier, wherein the journalsextend radially outward starting from the ring gear, wherein eachjournal is arranged between two roller elements accommodated at thehousing in order to support the ring gear on the housing in thetangential direction. In other words, the ring gear is to be understoodas a cylinder sleeve within the meaning of the invention, wherein theprevious comments presented with respect to the device also readilyapply to the planetary transmission.

The ring gear under load undergoes an excitation of vibrations due tothe meshing forces in the meshing of teeth between the ring gear and theplanet gears intermeshed therewith. In addition to these directexcitations, eigenmodes of the ring gear, which are also referred to asresonances, are excited, which could result in an unusual sound of theoverall system via the connection with the transmission housing. For thepurpose of acoustic decoupling and, therefore, in order to improve theacoustic properties and to decouple vibrations, in particular, theradially aligned journals arranged between the roller elements areprovided, which come to rest tangentially on the roller elements and aremovable in the radial direction in relation to the housing.Consequently, the excitation of vibrations is completely decoupled fromthe housing, wherein, simultaneously, a comparatively stiff support ofthe torque, which arises due to the load, on the housing is possible viathe journals and the roller elements. Therefore, a full functionality ofthe device and of the planetary transmission can be ensured also withouta stationary fixation of the ring gear on the housing, wherein, however,the acoustic excitation is simultaneously completely shielded from thehousing.

According to a further exemplary embodiment, the device is designed asan electric machine including a stator and a rotor, which isrotationally driveable in relation to the stator. The journals extendradially outward starting from the stator. Each journal is arrangedbetween two roller elements accommodated on the housing in order tosupport the stator on the housing in the tangential direction. In otherwords, the stator is to be understood as a cylinder sleeve within themeaning of the invention, wherein the previous comments presented withrespect to the device also readily apply to the electric machine.

During the rotary drive of the rotor arranged radially within thestator, the stator undergoes an excitation of vibrations. For thepurpose of acoustic decoupling and, therefore, in order to improve theacoustic properties and to decouple vibrations, in particular, theradially aligned journals arranged between the roller elements areprovided, which come to rest tangentially on the roller elements and aremovable in the radial direction in relation to the housing.Consequently, the excitation of vibrations is completely decoupled fromthe housing, wherein, simultaneously, a comparatively rigid support ofthe stator on the housing is possible via the journals and the rollerelements. Therefore, a full functionality of the device and of theelectric machine can be ensured also without a stationary fixation ofthe stator on the housing, wherein, however, the acoustic excitation issimultaneously completely shielded from the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the invention are explained in greater detail inthe following with reference to the drawings, wherein identical orsimilar elements are provided with the same reference characters,wherein

FIG. 1 shows a highly diagrammatic cross-sectional representation of aplanetary transmission according to a first example embodiment,

FIG. 2 shows a highly diagrammatic longitudinal sectional representationof the planetary transmission according to FIG. 1 ,

FIG. 3 shows a highly diagrammatic cross-sectional representation of anelectric machine according to a second example embodiment, and

FIG. 4 shows a highly diagrammatic longitudinal sectional representationof the electric machine according to FIG. 3 .

DETAILED DESCRIPTION

Reference will now be made to embodiments of the invention, one or moreexamples of which are shown in the drawings. Each embodiment is providedby way of explanation of the invention, and not as a limitation of theinvention. For example, features illustrated or described as part of oneembodiment can be combined with another embodiment to yield stillanother embodiment. It is intended that the present invention includethese and other modifications and variations to the embodimentsdescribed herein.

According to FIG. 1 and FIG. 2 , a device designed as a planetarytransmission 1 is shown in a highly diagrammatic way according to afirst example embodiment. The exemplary planetary transmission 1includes a sun gear 2, a cylinder sleeve-shaped ring gear 3 having aninternal toothing, as well as a planetary gear set having multipleplanet gears 4, which are rotatably mounted at least indirectly on aplanet carrier (not represented here). In FIG. 2 , a representation ofthe planet gears 4 and of the sun gear 2 is dispensed with for the sakeof simplicity.

Four radially outward extending journals 5 are arranged uniformlydistributed on an outer circumferential surface 16 of the ring gear 3.In the present case, two journals 5 are arranged essentiallyhorizontally opposite each other on the ring gear 3 and two furtherjournals 5 are arranged essentially vertically opposite each other onthe ring gear 3, wherein the journals 5 extend over nearly the entireaxial length of the ring gear 3, as is apparent in FIG. 2 .

The journals 5 extend radially into a particular recess 14 on thehousing 7 and are arranged between two particular roller elements 6 a, 6b, which are arranged in the particular recess 14 and enable atangential support of the ring gear 3 on the housing 7. Consequently, atorque acting on the ring gear 3 can be supported tangentially on thehousing 7 via the journals 5 and, depending on the direction of thetorque, via the particular roller element 6 a, 6 b. Simultaneously, eachjournal 5 is movable in the radial direction in relation to the housing7, wherein the particular journal 5 can roll on the particular rollerelement 6 a or 6 b depending on the load and depending on the radialdeflection of the ring gear 3. In other words, the journals 5 do notcome to rest against the housing 7 in the radial direction. The journals5 also rest against the roller elements 6 a, 6 b only as a function ofan applied torque such that a non-permanent contacting between thejournals 5 and the associated roller elements 6 a, 6 b and,consequently, an acoustic decoupling of the ring gear 3 from the housing7 are implemented.

The roller elements 6 a, 6 b are designed to be cylindrical and theiraxial length corresponds essentially to the axial length of the journals5. In particular, the roller elements 6 a, 6 b and the journals 5 aredesigned to be equally long. Consequently, there is linear contactbetween the journals 5 and the particular roller elements 6 a, 6 b. Theroller elements 6 a, 6 b can therefore come to rest against the recess14 of the housing 7 as well as against the journal 5.

Moreover, the journals 5 are press-fit into recesses—which is not shownin greater detail here—on the ring gear 3 such that a manufacture of thejournals 5 and of the ring gear 3 can be carried out in a simplifiedand, therefore, more cost-effective manner. Alternatively, it isconceivable to integrally join the journals 5, for example, via welding,with the ring gear 3.

The journals 5 as well as the roller elements 6 a, 6 b are also axiallytensioned in the housing 7 and, in fact, the journals 5 as well as theroller elements 6 a, 6 b come to rest, on the one hand, axially againsta shoulder 8 of the housing 7, which is integrally connected to thehousing 7, and, on the other hand, against a thrust washer 10. Thethrust washer 10 is secured in its axial position by a securing ring 9designed as a snap ring, which is accommodated in a circumferentialgroove 15 on the housing 7.

Roller elements 6 a, 6 b having different roller diameters can beutilized in order to compensate for manufacturing tolerances and adaptthe positioning of the ring gear 3 in the space. Consequently, at leasta portion of the roller elements 6 a, 6 b have unequal outer diameterssuch that, as a result, a play-free system is achieved.

As is highly diagrammatically represented in the second exemplaryembodiment according to FIG. 3 and FIG. 4 , the acoustic decoupling canalso be provided in an electric machine 12. In other words, the deviceis designed as an electric machine 12 and includes a stator 13 and apartially represented rotor 11, which is rotationally drivable inrelation to the stator 13. The only difference from the precedingembodiment is that the journals 5 are arranged on an outercircumferential surface 16 of the stator 13 and extend radially outwardstarting therefrom and, in so doing, are arranged between two rollerelements 6 a, 6 b in order to tangentially support the stator 13. Themode of operation for the vibration decoupling takes place similarly tothe comments presented with respect to the planetary transmission 1according to FIG. 1 and FIG. 2 .

Modifications and variations can be made to the embodiments illustratedor described herein without departing from the scope and spirit of theinvention as set forth in the appended claims. In the claims, referencecharacters corresponding to elements recited in the detailed descriptionand the drawings may be recited. Such reference characters are enclosedwithin parentheses and are provided as an aid for reference to exampleembodiments described in the detailed description and the drawings. Suchreference characters are provided for convenience only and have noeffect on the scope of the claims. In particular, such referencecharacters are not intended to limit the claims to the particularexample embodiments described in the detailed description and thedrawings.

Reference characters

-   -   1 planetary transmission    -   2 sun gear    -   3 ring gear    -   4 planet gear    -   5 journal    -   6 a first roller element    -   6 b second roller element    -   7 housing    -   8 shoulder    -   9 securing ring    -   10 thrust washer    -   11 rotor    -   12 electric machine    -   13 stator    -   14 recess on the housing    -   15 groove    -   16 outer circumferential surface

1-10. canceled
 11. A device, comprising: a housing (7); a cylindersleeve (3, 13) at least indirectly arranged at the housing (7), thecylinder sleeve (3, 13) comprising at least three radially outwardextending journals (5), each journal (5) arranged between a respectivepair of cylindrical roller elements (6 a, 6 b) accommodated at thehousing (7) in order to support the cylinder sleeve (3, 13) on thehousing (7) in a tangential direction, each journal (5) displaceable ina radial direction relative to the housing (7) by rolling on therespective pair of cylindrical roller elements (6 a, 6 b).
 12. Thedevice of claim 11, wherein the journals (5) are uniformly distributedon an outer circumferential surface of the cylinder sleeve (3, 13). 13.The device of claim 11, wherein there is linear contact between thejournals (5) and the respective pair of cylindrical roller elements (6a, 6 b).
 14. The device of claim 11, wherein the journals (5) arepress-fit into recesses on the cylinder sleeve (3, 13).
 15. The deviceof claim 11, wherein the journals (5) are integrally bonded with thecylinder sleeve (3, 13).
 16. The device of claim 11, wherein thejournals (5) and the respective pair of cylindrical roller elements (6a, 6 b) are arranged in an axial direction at least indirectly between ashoulder (8) of the housing (7) and a securing ring (9).
 17. The deviceof claim 16, wherein a thrust washer (10) is arranged between thesecuring ring (9) and the journals (5).
 18. The device of claim 11,wherein at least a portion of the roller elements (6 a, 6 b) haveunequal diameters.
 19. The device of claim 11, wherein: the device isconfigured as a planetary transmission (1) that comprises a sun gear(2), a ring gear (3), and a plurality of planet gears (4); the journals(5) extend radially outward starting from the ring gear (3); and eachjournal (5) is arranged between the respective pair of cylindricalroller elements (6 a, 6 b) accommodated at the housing (7) in order tosupport the ring gear (3) on the housing (7) in the tangentialdirection.
 20. The device of claim 11, wherein: the device is configuredas an electric machine (12) that comprises a stator (13) and a rotor(11), the rotor (11) rotationally drivable relative to the stator (13);the journals (5) extend radially outward starting from the stator (13);and each journal (5) is arranged between the respective pair ofcylindrical roller elements (6 a, 6 b) accommodated at the housing (7)in order to support the stator (13) on the housing (7) in the tangentialdirection.